1. Field of the Invention
This invention relates generally to utility meters, and is concerned in particular with an improved locking assembly of the type employed to prevent unauthorized access to such meters.
2. Description of the Prior Art
The conventional utility meter includes a housing containing the meter mechanism. A circular front port in the housing affords access to the meter mechanism in addition to displaying the meter dials. The circular housing port is surrounded by a peripheral flange adapted to mate in face to face abutting relationship with a peripheral flange on a glass bowl covering the front housing port. In order to maintain the glass bowl in place and thereby prevent unauthorized access to the meter mechanism, locking ring assemblies are employed to radially and axially confine the mating housing and bowl flanges.
Earlier locking ring assemblies, as disclosed for example in U.S. Pat. No. 4,008,585 (Lundberg), comprised split rings having their ends held together by a screw, with access to the screw being blocked by a separate lock housing designed to receive a side entry barrel lock. Although such assemblies offered reasonable security, the separate screws and lock housings proved difficult and awkward to assemble.
A later design, as disclosed in U.S. Pat. No. 4,611,478 (Carlson et al) eliminated the separate connecting screw and included the lock housing as an integral part of the ring. The ring was subdivided into mating semi-circular halves connected together by a hinge, and the lock housing was redesigned to accommodate front entry of the barrel lock. This arrangement was markedly easier to assemble, but the hinge connection between the ring halves offered less than adequate resistance to tampering by unauthorized personnel.
U.S. Pat. No. 4,828,300 (Agbay) discloses a further improvement, which retains the advantageous features of the Carlson et al design while eliminating the connecting hinge in favor of a redesigned rear flange having a special tapered configuration allowing the ends of the ring to be more easily spread during mounting and removal.
The foregoing prior art ring assemblies have conventionally been fabricated from cadmium plated heat treated low carbon steel. This material is relatively inexpensive, and thus raw material waste during manufacture has never been a major concern. A drawback with this material, however, is that it has a relatively low level of resistance to corrosion, which is a problem of increasing concern to utility companies, particularly where large numbers of customers are located along coastal or in industrial areas having corrosive environments.